This invention relates to a device including a motor whose speed is controlled by the energization and deenergization thereof in a pulsating manner.
Such a device of the type defined in the opening sentence is commercially available and frequently used in practice, and it is consequently known. For such a device reference can be made, for example, to the patent document EP 0 222 042 A1, FIG. 3.
The known device includes two separate switching means, of which a first switching means serves for connecting and disconnecting the coil arrangement of the motor in a pulsating fashion for the purpose of controlling the speed of the motor, and of which a second switching means serves to produce turn-off voltage transients across the coil arrangement. The known device further includes a control pulse generator for each of the two switching means. Two such switching means and two such control pulse generators are comparatively expensive and further have the problem that an undesired interaction may occur between the processes caused by the switching means, which may lead to invalidation of the results of these processes.